Displaying similar users

Question

Is it possible using Thinking Sphinx for it to output 8 (or other specified) similar users? For example I am on a Males profile page that lives in California. Under the Similar Users section it would show 8 other Males from California. It would be a random 8, no specific order. Just the gender and state location of the current user page needs to be the same.

I understand implementing geo distance with Sphinx, curious to how to show similar results based on user information. Does someone have an example of this?

Answer 1

You could take the geodistance approach as suggested by iMacTia - though I fear that may be overkill.

I'm presuming both state and gender are fields in your Sphinx index for users. This is in the context of your controller, where you're viewing @user and want similar users.

User.search(
  :conditions => {:state => @user.state, :gender => @user.gender}
  :without    => {:sphinx_internal_id => @user.id},
  :order      => 'RAND()',
  :per_page   => 8
)

Breaking down each of those options:

• Filter by the appropriate state and gender
• Don't include the current user (the model's primary key is an attribute in Sphinx named sphinx_internal_id).
• Random order
• Only eight results

Answer 2

First of all you'll need to implement sphinx geodistance like shown here. One you have done it (let's say you did it for the User table) you can now do:

@compatible_users = User.search "keyword", :geo => [@lat, @lng],
  :with => {'@geodist' => 0.0..10_000.0}

You can use the "keyword" that you prefer. @lat and @lng are current_user coordinates, @geodist is expressed in meters (so in this case it means "from 0 to 10km"). You'll also need the condition on the gender (sorry I don't know your model fields name, but this should not be a problem if you know how to use sphinx) Once you have the collection of @compatible_users, the task is now to randomly select some of them:

n = 8 # This is the number of users you want.   

# Ruby 1.9+
@ result = @compatible_users.sample(n)

# Ruby 1.8
@ result = @compatible_users.shuffle[0...n]

And you have your compatible users in @result :)

Keep in mind that if @compatible_users.size is lower than n you will get error using shuffle and a shorter array using sample. So you could need to check it and eventually do another sphinx search with a wider @geodist